Phase-sensitive x-ray imaging (PSI) is an exciting frontier of diagnostic imaging, promising highly detailed images of soft tissue while dramatically reducing radiation dose to the patient. The basic concepts behind PSI have been known for many years, but the technology is only now becoming practical for clinical use due to recent technical advances in x-ray tubes and digital detectors. The applicant will receive postdoctoral training in the Medical Imaging Research Center (MIRC) at the Illinois Institute of Technology (NT), one of the leading PSI research groups in the U.S. In this project, the applicant will take advantage of this opportunity to conduct a rigorous new study of one of the main types of PSI, namely in-line phase contrast imaging for mammography, or phase-contrast mammography (PCM). Specifically, the main goal of this project is to design, optimize, and build a PCM system and evaluate its performance. While it is clear from previous studies (and a commercial product on the market) that phase contrast effects can be seen in x-ray breast images, no comprehensive clinically relevant performance evaluations have been conducted. This research will use new breast data and computer models to simulate and build an optimized PCM in-line system and assess its ability to produce clinically useful images of mass density fluctuations in diseased tissue. The proposed project has the following specific aims: (1) Characterize the physical x-ray properties of breast tissue using a multiple-image radiography measurement system. (2) Use these measurements in conjunction with computational breast models and PCM in-line system simulations to optimize image quality by adjusting the physicalparameters of a benchtop system. (3) Build the optimized benchtop system and evaluate its capabilities for clinical application. Whereas conventional x-ray images (based on absorption) involve hazardous radiation absorption and provide limited sensitivity, x-ray phase contrast images show subtle differences in tissue mass density that are linked to the x-ray propagation speed through tissue. This phenomenon dominates absorption contrast by more than 1,000 times at higher x-ray energies, such as those used in general radiography, where breast tissue absorbs far less ionizing radiation. These properties make low-dose phase-contrast mammography an exciting possibility. PUBLIC HEALTH RELEVANCE: